1. Field of the Invention
The invention relates to catheters, in particular leader catheters or stimulation catheters that are used to form a channel in the body tissue of a patient. In particular the present invention relates to those catheters that may be controlled during the formation of a channel in the body of the patient.
2. Description of the Related Art
A number of approaches for controlling catheters are known from the state of the art. There are in particular known catheters which have a tension wire that is guided in the longitudinal direction of the catheter and is attached to its distal end in such a way that a certain longitudinal section of the catheter is curved due to tension on the tension wire.
Such catheters are used especially in the venous or arterial vascular system of a patient or in other body cavities, the path of the catheter on insertion being predetermined primarily by vascular geometry. The controllability of such a catheter serves essentially in the search for certain vascular branches or the search for targeted areas in body cavities.
Catheters designed to form a channel in a patient's body tissue are used, for example, in implantation of electrodes for deep brain stimulation (DBS) in the brain of a patient. On insertion, the catheter must first form the implantation channel in the patient's brain, which is why the path of the catheter is not determined in advance, unlike the situation on insertion into the vascular system of a patient or into body cavities.
Furthermore, the catheter must follow a path that is accurately predetermined by the surgeon in order to save and/or bypass critical tissue areas and regions, for example.
The controllability of traditional catheters is not sufficient for this task; in particular, the radii of curvature of traditional catheters which are adjustable in this context are only inadequately variable and therefore do not allow precise and accurate channel formation. Controllable catheters in the state of the art exert an unacceptable additional normal force on the body tissue—in this case cerebral tissue—precisely when there is a change of direction and a subsequent induction of forward force.